(a) Field of the Invention
The present invention relates to a construction method for installing underground pipes for high-tension cables by using a trough, capable of installing high-tension cables by excavating the ground. More particularly, the present invention relates to a construction method for installing underground pipe for high-tension cables by using a trough, which can reduce the construction cost by omitting installation work for temporal structures, can improve working efficiency by shortening the period of construction, can facilitate repair and maintenance work while preventing the underground pipes used for installing the high-tension cables from being broken, and can enable stable construction work for other facilities.
(b) Description of the Related Art
In general, a sand placing scheme is mainly used to install underground pipes.
FIGS. 1 and 2 are views showing underground pipes 1 installed through the sand placing scheme. Referring to FIGS. 1 and 2, an excavation trench is formed by performing excavation work such that inclined surfaces are formed at left and light sides of the excavation trench at a predetermined angle and a predetermined depth. Then, H beams 3a are installed at a predetermined interval to prevent an accident caused by the landslide occurring at both sides of the excavation trench and to protect the underground pipes 1 used for installing high-tension cables therein. In addition, transverse plates 3b are provided between the H beams 3a, thereby establishing a temporal structure 3.
Then, the underground pipes 1, which are used for installing the high-tension cable, are installed on the bottom of the excavation trench by alternately placing the underground pipes 1 and sand s. After that, concrete 130 is casted onto the underground pipes 1 and then the temporal structure 3 is removed.
If the underground pipes are installed through the sand placing scheme, the construction cost can be reduced. However, since the concrete is casted onto the underground pipes after pure sand is placed together with the underground pipes, strength of the construction may be remarkably lowered. In addition, when other facilities are installed in the vicinity of the underground pipes, sand is collapsed at the side of the excavation trench, so that the underground pipes are easily damaged.
In order to overcome the above problem, a concrete casting scheme is recently used to install the underground pipes. According to the concrete casting scheme, after forming the excavation trench using an excavator and installing the temporal structures, a form is installed in the excavation trench, a cable is installed in the form, and concrete is casted into the form.
However, although the concrete casting scheme can improve strength of construction as compared with the sand placing scheme, the construction cost may be increased. In addition, since the temporal structures must be uniformly installed over the whole construction area due to the concrete casting, the cost for installing the temporal structures may be increased and labor force is wasted, so that working efficiency is lowered.
In addition, it takes much time to cure the concrete in the form, so the working efficiency is remarkably lowered and repair work is very difficult.
Further, the construction cost is also increased due to concrete casting work.